Many of the parameters that can be determined from cardiac output related waveforms, e.g., peripheral pressure waveforms, are important not only for diagnosis of disease, but also for “real-time,” i.e., continual, monitoring of clinically significant changes in a subject. Various methods exist to identify and/or calculate these parameters based on analysis of various features in cardiac output related waveforms. Few hospitals are without equipment that employ these methods to monitor one or more cardiac output related parameters in an effort to provide a warning that a subject's condition is changing.